The new mixed content blocker is one of Firefox 23's security enhancements. When a webpage contains a combination of both secure (HTTPS) and non-secure (HTTP) content, it blocks the non-secure content and its new Network Monitor tool will be welcome by developers as it reveals how long it takes for the individual website components to load, helping you in pinpointing problems.

One minor change has caused a bit if a stir among developers. The HTML blink tag that, reasonably enough, made text blink on and off has finally been removed. It might have been assumed that this would a welcome change that simply ensured compliance with a W3C requirement. Instead there's already several add-ons to restore this facility.

Another controversial change, which we discussed last month is that the “Enable JavaScript” preference checkbox has been removed and JavaScript is enabled by default. It seems, however, that this doesn't actually guarantee that JavaScript will always be available - which developers would have found a welcome simplification - because you can still turn JavaScript off if you dig a little deeper. Firefox 24 adds a new facility - that of being able to see how a page looks when JavaScript is disabled from the options panel in the debugger. When you disable JavaScript for the current tab this persists until you either close the tab or the developer tools.

The Hacks.Mozilla blog gives details of "a slew of new features" to developer tools in Firefox 24 for Windows, Mac and Linux:

Less Console Clutter

The console will now clear all of the existing logs when you refresh the page. If you need logs to persist across reloads, this behavior is toggle-able in the options panel.

Source maps

Source maps are now enabled by default although you can toggle them on and off if you need to debug the JavaScript generated by your tool or compiler rather than the original source.

To resolve issues with Internet Explorer, the source map specification has been updated so that you link a source map to its script with //# sourceMappingURL=... rather than the deprecated //@ sourceMappingURL=....

The text of a source mapped source will now be loaded from its source map’ssourcesContent property, if it exists.

Debugger

Frozen, sealed, and non-extensible objects are now visually distinguished in the debugger’s variables view:

When stepping out of a stack frame in the debugger, you will now see either the return value or the exception thrown (depending on why you are exiting the frame) in the variables view labeled <return> and <exception> respectively.

Network Manager

The ability to filter by types of requests in the network monitor has been improved. Also the total number of requests, file sizes, and response times are now listed and update with your filters, so you can see just how many KBs you are requesting on every page load.

Profiler

You can now control the profiler from your web app’s code base via console.profile() to start a new profile, and console.profileEnd() to end it.

The Firefox 24 for Android beta has features to help users share content. Extending the support for WebRTC it now includes the WebRTC components DataChannels, PeerConnection and GetUserMedia to enable developers to integrate real-time communications across the Web.It also provides NFC (Near Field Communications) Bump to share Firefox tabs with another NFC-enabled Android phone by “bumping” them together; and Quickshare which creates a space in the Share menu from a list of sharing services, such as email, SMS and social media, available on the user’s device. There are also improvements to Reader and Reading List.

Finally, as we pointed out when Firefox 23 beta was first announced, Mozilla has redesigned the Firefox logo, optimizing it for small screens and lower resolution devices.

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